The invention set forth in this specification pertains to new and improved check valves. It is primarily directed toward check valves which are specially adapted to be installed within drains such as floor or pavement type drains.
Such drains are normally constructed so as to utilize either a housing leading to an appropriate outlet pipe or a portion of such a pipe beneath a surface to be drained to hold a perforate plate serving to prevent comparatively large objects from entering such a drain. On occasion back flow may occur into such drains. Whenever such back flow occurs there is a degree of danger of a health hazard. Further, whenever such back flow occurs there is the distinct possibility of damage to any item or items located on a floor or pavement adjacent to such a drain. As a consequence of this there is an increasing recognition of the desirability of utilizing check valves in connection with floor, pavement and similar drains in order to prevent back flow.
It is considered that conventional check valves are not reasonably adapted for use in such drains for any one of a variety of different reasons. Such conventional check valves may be constructed in many different ways. As they are normally constructed they utilize specially formed valve or valve housing parts or components which cannot readily be installed within a drain or drain structure already located in a floor or pavement without significant difficulty. Although it is possible to especially construct drains or drain structures to be used with known types of check valves this is not considered desirable for economic reasons, and in addition, it is frequently desirable to install a check valve within an already existing or installed drain or drain structure.